1. Field of the Invention
The present invention relates to a device for monitoring the performance of a plasma burner with a view to warning and/or taking evasive action in the event of the appearance of fault conditions in the plasma arc of such a burner or the appearance of conditions presaging a fault in such a burner.
2. Discussion of Prior Art
One problem when using a plasma burner for cutting is that there is no feedback to the user in the case of a short-circuit or a worn nozzle. The cutting efficiency of the burner deteriorates but the "handle" of the burner is unchanged and a substantial amount of inferior cut material may result before the user realises that a less than optimum arc is being generated by the burner. With a mechanical cutter however, a reduction in cutting efficiency is immediately sensed by the operator making it an easy matter to detect (and thus correct) fading cutting efficiency.
In the case of robot-controlled cutting equipment it is highly desirable to have some automatic means for monitoring the cutting efficiency of the equipment and in the case of plasma burners there has, heretofore, been no satisfactory way of monitoring the burner efficiency so that robot-motivated action can be taken to prevent sub-standard cuts being made.
At the present time the nozzle of a plasma burner is replaced after a certain period of use, and the only inspection of used nozzles that normally takes place is an after-inspection following replacement.